Electric switch



March 13, 1934. s. SCOTT ELECTRIC SWITCH Filed Augu 5, 1930 I N V EN TOR. George $60 ff A TTORNEY.

The

sense being for reversal.

Patented Mar. 13, 1934 PATENT OFFlCE ELECTREC SWITCH George Scott, London, England, assignor to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application August 5, 1930, Serial No. 473,206 In Great Britain April 4, 1930 6 Claims.

This invention relates to electric switches, particularly for use with portable machines and tools, and more especially to switches of the reversing type.

invention further relates to electric switches as disclosed in the copending applica-' tion of Leon F. Meunier and Clarence J. Dresser Serial No. 343,972, filed March 2, 1929, and issued as Patent 1,817,013 on August 4, 1931.

w According to the invention disclosed in the said prior specification, the switch has a single control member which is movable in two distinct senses, movement in one sense being for opening and closing the line and movement in the other The senses of movement are angular and axial.

Although a switch constructed according to the said prior specification is practically fool proof because axial movement is impossible until the 'switch handle is first placed in or turned to the off position and during axial movement the handle cannot be turned to the on position until it has reached a predetermined position in such movement, it is possible to open up the switch casing, since it is usually constructed in two parts bolted or screwed together, while current is flowing.

The object of this invention is to provide a vsafety device in said casing whereby taking apart 39 of said casing is rendered impossible while current is flowing.

To this end. therefore, a hooked member mounted on the switch shaft is adapted to engage with a stud or the like mounted on each part of the casing when the switch handle is in the on position and to disengage when the said switch handle is in the off position.

In order that the invention may be fully understood, it will now be described with reference to 4 th accompanying drawing in which Figure 1 is a plan view of one form of locking device constructed in accordance with this invention and shown applied to a switch casing having a portion of its top plate cut away.

Fig. 2 is a section on the line 2-2 of Figure 1,

and Figure 3 is a similar view to Figure 2 but showing the locking device in a different position.

The switch mechanism is similar to that described in the said prior specification except 0 that the switch is made to suit three phase A. C. circuits and a detailed description thereof is not considered necessary.

a and b are the top and bottom plates re --spectively of the switch. 0 is the switch shaft which is adapted to be moved angularly and axially. cl is the switch lever fitted to said shaft 0.

The inner end of the shaft 0, which is of square section, is adapted to enter the squared socket e of the locking device. The said socket e is formed with a peripheral flange which is adapted to enter two semi-circular grooves 9, one of said grooves being formed in each plate of the casing, and be rotatably mounted thereon.

Formed in one with or secured to the socket e a double hooked member 71.. 7', i are studs secured in the two plates a and b and over which the said hooks 71. are adapted to engage.

In Figure 2 the shaft c is in the off position and the hooks h are rotated out of engagement with the studs 9', 7'.

In Figure 3 the switch shaft 0 is in the on position and it will be seen that the hooks h, h are engaging the studs 9', 7', thereby making it impossible to remove either top or bottom plate.

If desired, a pair of locking devices may be provided, one at each end of the casing.

When the switch is in running position and the current is flowing, the hooked member It will be engaging the studs 7', 7' and therefore it will be impossible to disengage the parts of the casing, but as soon as the switch handle has been moved to the off position the studs 7', 9 will be freed and the casing can be opened.

I claim as my invention:

1. An electrical switch comprising a casing in two parts adapted to enclose switch mechanism, a control member movably mounted on said casing, projecting members on said casing parts, and means comprising a doublehook member engaging said projecting members to lock said casing parts together when said control member is in the on position.

2. An electrical switch comprising a casing in two parts adapted to enclose switch mechanism, a control member mounted for axial and angular movement in said casing, clamping means operable on angular movement of said member,

means on said casing parts engaged by said casing parts together when said shaft is in the on position.

4. An electrical switch comprising a casing in two parts, a control shaft mounted for axial and angular movement in said casing, a hooked member in line with and engaged by said shaft to be operated on angular movement of the latter to lock said casing parts together, said parts providing bearings for said hooked member preventing axial movement of the same with said shaft and studs to be engaged by said member.

5. An electrical switch comprising a casing in two parts providing therebetween a bearing having an annular recess transverse to the bearings, studs on said parts adjacent said bearing, a double hook locking member rotatably mounted in said bearing and having a flange received in said annular recess, and a control shaft in said casing mounted for both axial and angular movement, said shaft and said member having parts in telescoping engagement whereby said shaft rotates said member when it is moved angularly but slides relative thereto when moved axially.

6. An electric switch comprising a casing in two parts adapted to enclose switch mechanism, a control member mounted for axial and angular movement in said casing, a locking member keyed to said control member, a bearing for holding said locking member against axial movement and means on each part of the casing adapted to cooperate with the locking member in one of its positions to lock the casing parts.

GEORGE SCOTT. 

